THE fascination that so many have with Jimmy Buffett is very much like the allure of a poverty-stricken island country that depends on tourism for its fortunes. Although Buffett’s Margaritaville is an OK place to visit, most wouldn’t want to live there.

In concert at Madison Square Garden Monday, Buffett showed himself to be a hollow man: all style, no substance. A cheerleader clown living on the glory of a few good cover songs and a handful of his own compositions.

Up front it should be noted that the mostly filled Garden was in a panic for Buffett’s antics. They love this man, not only for his songs, but for the hedonistic lifestyle he represents, and which they envy. With the rabid devotion of cultists, Buffett’s followers call themselves ”Parrotheads” (probably for the bird-brained notion of taking Buffett seriously in the first place).

Although most were old enough to know better, they still waddled to the modified calypso, reggae and country beats as Buffett attempted to rouse them with a good imitation of Richard Simmons in binding shorts. Although he isn’t the greatest songwriter, Buffett has a few great songs. He also has his share of stinkers and tunes with moronic lyrics such as ”Come back to Jamaica, we made a big mistaka” and ”Creole-la in my soul-la” – ouch. These are hardly the clever lines such as ”A white sport jacket and a pink crustacean” or ”We are the people our parents warned us about” that made the world first take notice of the man.

Whether it was the fault of the sound man or Jimmy himself, the singing beach bum’s vocals were pretty horrid. As he worked his narrow range – that is, a nasal tenor – the sonic quality was more akin to that produced by a wax-paper-covered comb than to your usual concert fare. But it didn’t really matter, since the fans were mostly singing along (almost as badly), and the 13-piece band often overpowered the man.

Buffett played all his obvious hits about beaches, bars, boats and babes, such as ”Grapefruit and Juicy Fruit,” ”Why Don’t We Get Drunk and Screw,” ”Margaritaville” and ”Cheeseburger in Paradise.” All were well-received, but where he deserved the cheering squawks of the Parrothead army was on the powerful ballad ”Son of a Son of a Sailor.” He was also pretty fair on a reggae-beat rendition of Van Morrison’s ”Brown Eyed Girl,” played in the first set before the intermission.

Otherwise, the too-long, almost-three-hour, all-you-can-eat Buffett show was filled with inferior material like ”Math Suks,” a cover of James Taylor’s ”Mexico,” a half-hearted ”Volcano” that yielded to ”Twist and Shout” between eruptions, and the sappy, mush-mouthed ballad ”Last Mango in Paradise.”

Buffett isn’t much of a singer; he isn’t outstanding on the six-string; his stage patter includes stimulating repartee such as ”How ya doing?” and he requires a huge band to deliver simple music. This is a man who depend on the kindness of strangers, who continue to buy his mediocre albums and go to worse and worse concerts because they admire the lifestyle he sings about. It is a strange symbiosis that definitely keeps Jimmy happy, and even makes the Parrotheads smile.